The device pertains to a disposable tubing kit that is attachable to a syringe of an automatic injection device. Automatic injection devices, such as applicants' device described in U.S. Pat. No. 6,099,502 and incorporated by reference herein, are used to deliver fluids such as saline and contrast agents through a catheter to a patient. The devices typically include a motor-driven linear actuator that forces a plunger through a syringe, thereby creating a desired fluid flow into the patient. For sanitation purposes, the syringe and all associated tubing between the patient and the syringe are disposable.
Preparing the automatic injection device for operation is a time-consuming process. Various tubes must be connected together and to the device. The operator preparing the injection device for operation must be careful to ensure that the connections are tight and that none of the tubes are pinched or otherwise blocked. Furthermore, during the assembly process, the operator will prime various subassemblies with saline and contrast before connecting them to other subassemblies. Priming is done to prevent air from being introduced into the patient. Intermittent priming steps are performed so that fluid-to-fluid connections may be made at predetermined assembly steps. For purposes of this discussion, a fluid-to-fluid connection between two components is made by priming each component so that menisci form at their open ends. The ends are then connected together, thereby merging the menisci and ensuring no air is introduced into the connection.
Priming the subassemblies is performed by injecting a desired fluid into the subassembly until the fluid exits the opposite end. The exiting fluid is usually directed into a waste pan, but occasionally spills onto the floor, creating a potential slip hazard, or onto the patient, who is awake during most of the procedures involving the automatic injection device. In addition to creating slip hazards or causing discomfort to the patient, there is growing interest in minimizing the presence of open fluid containers in medical environments. This is especially true for bodily fluids, such as blood, which present a potential biohazard.
Once assembled, the components are again primed with fluid to prevent air from being injected into the patient. While priming, the operator taps on the various components in an attempt to dislodge air bubbles from their inner walls. The entire set-up process typically takes 10 to 15 minutes and requires a trained operator. Opportunity for error exists even when the set-up is carefully performed by a trained operator.
Some completely assembled, disposable kits are available that include a syringe that is pre-loaded with contrast agent. These kits overcome some of the aforementioned difficulties but present their own challenges to the manufacturer. All medical devices must be delivered sterile and are thus sterilized prior to shipping. Present methods of sterilization include heating using wet or dry autoclaving, gamma irradiation, or EtO sterilization. Each method has drawbacks. Dry autoclaving requires very high temperatures to overcome the lack of heat transfer inherent in dry systems. Wet or steam autoclaving causes dimensional increases in plastic components as the moisture penetrates the plastic and a subsequent decrease as the moisture later escapes. Steam autoclaving further uses a temperature which may cause the polymeric parts to deform. Gamma irradiation requires the use of gamma-stable components and, further, degrades contrast agents, and EtO requires a subsequent out-gassing step to remove byproducts of the sterilization process, and is also expensive, inflexible and difficult to verify or control.
Regardless of whether the syringe is pre-filled, once the set-up is complete, the physician positions a catheter into the patient. The use and type of the catheter varies depending on the procedure being performed. For example, the catheter may be used to deliver contrast agents, using the aforementioned injection device, or to provide a guide for routing bioptomes, ultrasonic imaging probes, or balloon devices.
Some of the devices require fluid flow, such as the balloon devices, and are connected to special manual syringes. These special syringes are called “inflators” and use a plunger that is manually advanced using a rod that is threaded into a handle to allow the operator to advance the plunger using very small, controlled increments. However, these threads also give the physician such a mechanical advantage as to take away the “feel” of the balloon inflation. Thus, the physician cannot feel the effect the balloon is having on the wall of the vessel it is stretching. For example, the physician cannot feel a calcium deposit cracking. The special syringes typically include a pressure gauge but it is located on the syringe itself and is impractical for the physician to monitor the gauge as he or she is often watching an image of the balloon being inflated on a monitor. It would be advantageous to use the automatic injection device to accomplish controlled injections of fluid for purposes such as inflating balloons so that a greater degree of inflation accuracy and control is achieved and so a more precise and accurate feedback loop is attained. However, automatic injection devices are generally constructed and arranged to accommodate a large-capacity syringe such as the syringe used to inject contrast agent. This type of syringe is too large to be used for balloon inflation because the injection device cannot move the linear actuator over a short enough distance and with the necessary precision and accuracy for a balloon inflation procedure. Additionally, the larger syringe exhibits greater compliance. To provide the necessary accuracy, a smaller syringe would have to be used so that a given linear distance traveled by the actuator results in a much smaller volume of liquid being injected. However, a small syringe, such as the manual syringe used to inflate a balloon, is not compatible with the present automatic injection devices.
There is a need for a device and method for reducing the set-up time associated with using an automatic injection device.
There is also a need for a device that minimizes the chances of error by an operator in setting up an automatic injection machine for use.
There is a further need for a device and method that improves management of waste while performing catheter-based surgical procedures.
There is thus a need for an adapter that would allow the automatic injection device to be used to inject small, precisely measured and controlled amounts of fluid.